Sun, 05 Apr 2009

I'm not a Mac person, but Dave hit this a few days ago on a brand
shiny new Mac Mini and it was somewhat traumatic. Since none of the
pages we found were helpful, here's my contribution to the googosphere.

Ubuntu through Intrepid (supposedly this will be fixed in Jaunty;
we didn't test it) have a major bug in their installer which will
render Macs unable to boot -- even off a CD.
(I should mention that the problem isn't limited to Ubuntu --
I did see a few Fedora discussions while I was googling.)

What happens is that in the grub install stage, gparted writes the
partition table (even if you didn't repartition) to the disk in a format
that's incompatible with the Mac boot loader.

There's some discussion in a couple of Ubuntu forums threads:
8.04 won't boot
and
Intel Macs with Hardy 'no bootable devices'
and all of them point to an open source Mac app called
rEFIt (yes, it's supposed
to be capitalized like that). But Dave had already tried to install
rEFIt, he thought, unsuccessfully (it turned out it was installed but
wasn't showing its menu properly, perhaps due to an issue of his Apple
keyboard not properly passing keys through the USB KVM at boot time.
Ah, the Apple world!)

Anyway, none of the usual tricks like holding Alt or C during boot
were working, even when he took the KVM out of the loop. After much
despair and teeth gnashing, though, he finally hit on the solution:

Cmd-Option-P-R during boot to reset the Parameter RAM back
to factory defaults.

We still aren't clear how the Ubuntu installer managed to change the
Parameter RAM. But a couple of iterations of Cmd-Option-P-R cleared
up the Mini's boot problem and made it able to boot from CD again,
and even made rEFIt start showing its menu properly.

There's one more step: once you get the machine straightened out
enough to show the rEFIt menu, you have to right-arrow into rEFIt's
partition manager, hit return, and hit return when it asks whether to
synchronize the partitions. That will reformat the incorrect
gparted-format partition table so the Mac can use it.
(And with any luck, that is the last time that I will EVER have
to type rEFIt!)

(Though a better way, if you could go back and do it over again, is
to click the Advanced button on the last screen of the Ubuntu live
installer, or else use the alternate installer instead. Either way
gives you the option of writing grub to the root partition where
you installed Ubuntu, rather than to the MBR, leaving you much less
horked. You'll still need to rewrite the partitions with rEFIt (grumble,
I knew I wasn't quite through typing that!) but you might avoid the
Parameter RAM scare of not being able to boot at all.)

That's the story as I understand it. I hope this helps someone else
who hits this problem.